Electric alarm and call-bell system.



J. H. FIELD. ELECTRIC ALARM AND CALL BELL SYSTEM. APPLICATION FILED IAN. 25, 1909.

976,562. v Patented N0v.22, 1910.

Q a :11 111 I -T WITNESSES: INVENTOF? Jimzea' UNITED STATES PATENT OFFICE.

JAMES HASLIP FIELD, OF VICTORIA, BRITISH COLUMBIA, CANADA, ASSIGNOR TO THE CANADIAN TAYLOR AUTOMATIC FIRE ALARM AND CALL BELL COMPANY, LIMITED,

A CORPORATION.

ELECTRIC ALARM AND CALL-BELL SYSTEM.

Specification of Letterslatent.

Patented Nov. 22, 1910.

Application filed January 25, 1909. Serial No. 474,142.

To all whom it may concern:

Be it known that I, JAMES HAsLrr FIELD, a subject of the King of Great Britain, residing at Victoria, in the Province of British Columbia, Canada, have invented a new and useful Electric Alarm and Call- Bell System, of which the following 1s a specification.

This invention relates to an electrlc fire alarm system of that class wherein manual switches are used to close the circu1t and ring an alarm or where the circuit is automatically closed by thermostats, when the temperature surrounding any of them is raised beyond the limit for which it has been set, and the invention is especially directed to the improvement of that system of wiring wherein with an open circu1t separate connections are made from each thermostat or group of thermostats or from any manual switch or switches to each drop of an electromagnetic annunciator so that the source of any alarm will be indicated.

The evident objection to the open circuit system of wiring is that if a wire becomes disconnected'or the operating battery weak, no warning is given: should the fault occur in a common wire all-manual switches or thermostats other than those on the battery side of it are rendered inoperative to transmit an alarm, or if the fault occurs in an annunciator wire the manual switches or thermostats connected by that wire to that particularannunciator drop are similarly rendered inoperative. This defect is at pres ent partially overcome by placing the common wire in a supplementary circuit in which is a constant current battery and relay that will when a fault occurs in the circuit, close a trouble bell circuit to ring an alarm. With this arrangement should a fault occur in a common wire though the trouble bell rings an alarm yet all manual switches or thermostats other than those on the battery side of the fault are rendered inoperative. In the system which is the subject of this application these objections are overcome by connecting the return wire of the supplementary or test circuit to a secondaryfcontact in each manual switch or thermostat. With this provision and by placing the constant currentbattery at the extreme op osite end of the circuitto that in which is the trouble bell relay, when the circuit is in perfeet working order the manual switches or thermostats will close the open circuit and ring an alarm in the ordinary way, but if any defect occurs in the line the trouble bell will indicate it at once, but beyond that the manual switches or thermostats are not rendered inoperative as will be explained later. The following specification fully describes the system reference being made to the drawing by which it is accompanied which represents diagrammatically an alarm bell system having my improvements. In this drawing 2 2 2 represents manual switches such as push buttons, or thermostats of any approved type, which may be distributed about the rooms and passages of a building either separately or in groups, each manual switch or thermostat or group of switches and thermostats being connected by separate wires 5 to a separate drop of the annunciator 6 and thereafter through an alarm bell 7 to the positive pole of the operating battery 8. The contacts 4 of the thermostats or switches 2 are connected by a common wire 9 to the negative pole of the same battery 8-. This is the common form of open circuit connection. When any manual switch is operated to close the circuit or when any thermostat is exposed to a tem-- perature in excess of that for which it has been set and expands and engages its contact 4 the circuit will be closedand an alarm been made to remedy this defect b placing.

the common wire 9 under test by including it in a supplementary circuit 11 in which a constant current is maintained by a battery' 10 in which supplementary circuit is a relay 13 the armature of which holds open a circuit 15 in which is a trouble bell 16. As no reason exists for placing this constant battery 10 at any particular part of the circuit 1t is usually located adjacent to the relay I which controls the trouble bell circuit, which again is naturally placed adjacent to the battery 8 which operates the alarm bell and annunciator of the general circuit. Stress is laid on this point for a reason which will the common wire 9 of the generafcircuit be explained later. With addition if should become disconnected the trouble bellwill ring, but, as before, all switches -'or therv most'atsjother than. those on the battery side of thefault are rendered inoperative and if any of the .wires 5 which connect the:

switches or thermostats to the annunciators should break they are not only inoperative but no intimation is given of the fact. To remedy these defects in .what is otherwise a convenient system I provideeach manual switch or thermostat with secondary contacts 12, which secondary contacts are preferably set to be brought into engagement on a further movement of the switch or thermo: stat, and thesefsecondary contacts are all connected in the return wire 11, of the supring, the current drawing at the opposite end of the circuit to the relay. With this arrangementif one of the Wires 5 from a manual switch or ther-. 'mostat to the annunciator is disconnected,

when any one of them is operated or operates to ring an alarm it cannot do so on en gagement with the first contact 4:; but when brought into engagement with the seconda contact 12, althou h the alarm hell 7 will not EIOIII the battery 10 will be short circuited through the contact of 4: and

' the circuit 15 and 12, the relay will release its armature, close cause the trouble bell 16 to ring. Aga n if the fault is in the common Wire 9 an alternative course is provided for the current from 7 through the supplementary circuit ll while if the supplemenbattery tary circuit 11 becomes disconnected or its 10 istoo weak, the relay 13 will release its armature to close the trouble bell circuit 15 and ring the trouble bell 16.

Having now particularly described my invention and the manner of its operation, what I claim as new and desire to be protected in by Letters Patent, is:

1. In an electric alarm system, a normally open circuit including a source of electric energy, an indicator, a switch, and line wires connecting the aforesaidparts, a closed circuit includ' g a source of electric energy, one of said line wires of said normally 0 en circuit and an auxiliary line wire toget er with a translating device in said auxiliary line wire in virtue of which said switch ma close said normally open circuit without eii fecting said translating device of said closed circuit. I

2. ,Inan electrical alarm system,- a normally open circuit including a source of electric energy, an indicator, a switch, and line wires connectin the aforesaid parts, a closed circuit including a source of electric energy, one of said line wires of said normally open circuit, an auxiliary line wire together with a translating device in said auxiliary line wire in virtue of which said switch may close said normally open circuit without affecting said translating device of said closed circuit, and. means cooperating with said switch for bringing said translating device into said normally open circuit at times. I

In testimony whereof I have signed my name to this specification inthe presence of two subscribing witnesses.

J AMES HASLIP FIELD.

Witnesses: v

GEORGE PARKINSON, Jos. PEIRSON. 

